ServerString.java

   1 package be.nikiroo.utils.serial.server;
   2
   3 import java.io.IOException;
   4 import java.net.Socket;
   5 import java.net.UnknownHostException;
   6
   7 import be.nikiroo.utils.Version;
   8
   9 /**
  10  * This class implements a simple server that can listen for connections and
  11  * send/receive Strings.
  12  * <p>
  13  * Note: this {@link ServerString} has to be discarded after use (cannot be
  14  * started twice).
  15  *
  16  * @author niki
  17  */
  18 abstract public class ServerString extends Server {
  19         /**
  20          * Create a new server that will start listening on the network when
  21          * {@link ServerString#start()} is called.
  22          *
  23          * @param port
  24          *            the port to listen on, or 0 to assign any unallocated port
  25          *            found (which can later on be queried via
  26          *            {@link ServerString#getPort()}
  27          * @param ssl
  28          *            use a SSL connection (or not)
  29          *
  30          * @throws IOException
  31          *             in case of I/O error
  32          * @throws UnknownHostException
  33          *             if the IP address of the host could not be determined
  34          * @throws IllegalArgumentException
  35          *             if the port parameter is outside the specified range of valid
  36          *             port values, which is between 0 and 65535, inclusive
  37          */
  38         public ServerString(int port, boolean ssl) throws IOException {
  39                 super(port, ssl);
  40         }
  41
  42         /**
  43          * Create a new server that will start listening on the network when
  44          * {@link ServerString#start()} is called.
  45          *
  46          * @param name
  47          *            the server name (only used for debug info and traces)
  48          * @param port
  49          *            the port to listen on
  50          * @param ssl
  51          *            use a SSL connection (or not)
  52          *
  53          * @throws IOException
  54          *             in case of I/O error
  55          * @throws UnknownHostException
  56          *             if the IP address of the host could not be determined
  57          * @throws IllegalArgumentException
  58          *             if the port parameter is outside the specified range of valid
  59          *             port values, which is between 0 and 65535, inclusive
  60          */
  61         public ServerString(String name, int port, boolean ssl) throws IOException {
  62                 super(name, port, ssl);
  63         }
  64
  65         @Override
  66         protected ConnectActionServer createConnectActionServer(Socket s) {
  67                 return new ConnectActionServerString(s) {
  68                         @Override
  69                         public void action(Version clientVersion) throws Exception {
  70                                 for (String data = rec(); data != null; data = rec()) {
  71                                         String rep = null;
  72                                         try {
  73                                                 rep = onRequest(this, clientVersion, data);
  74                                         } catch (Exception e) {
  75                                                 onError(e);
  76                                         }
  77
  78                                         if (rep == null) {
  79                                                 rep = "";
  80                                         }
  81
  82                                         send(rep);
  83                                 }
  84                         }
  85
  86                         @Override
  87                         protected void onError(Exception e) {
  88                                 ServerString.this.onError(e);
  89                         }
  90                 };
  91         }
  92
  93         /**
  94          * This is the method that is called on each client request.
  95          * <p>
  96          * You are expected to react to it and return an answer (NULL will be
  97          * converted to an empty {@link String}).
  98          *
  99          * @param action
 100          *            the client action
 101          * @param clientVersion
 102          *            the client version
 103          * @param data
 104          *            the data sent by the client
 105          *
 106          * @return the answer to return to the client
 107          *
 108          * @throws Exception
 109          *             in case of an exception, the error will only be logged
 110          */
 111         abstract protected String onRequest(ConnectActionServerString action,
 112                         Version clientVersion, String data) throws Exception;
 113 }